FAQ

Q: How many times can a EZReball™ preform be used to reball a BGA?A: The EZReball™ preforms are designed for single use only.

Q: What considerations should I be aware of if I am planning to order a customized EZReball™ reballing preform? A: Present the BEST staff with the mechanical datasheet or the ball diameter and pitch along with the pattern or matrix and after order entry we’ll let you review the design prior to processing.

Q: We have a unique BGA package that I cannot find on the web site. Is BEST able to provide custom preforms?A: BEST can make almost any custom preform pattern as long as the pitch is 0.8mm or greater. Unlike all other preforms there is no development fee for ordering a new EZReball pattern. What is required are the mechanicals for the package.

Q: What is the average processing time for a device using the EZReball process?A: From start to finish including the site preparation time, the placement of the EZReball preform, reflow, cleaning and inspection is from 5-7 minutes. This is about 1-2 minutes faster than the paper preform technique which requires the scrubbing off of the paper preform.

Q: How do I properly prepare a package for reballing?A: There are a variety of device preparation techniques. To find a more complete description on this as well as other processes look here. Our BGA Reballing Kit includes a complete detailed instruction manual for preparing a device for reballing.

Q: How do I clean the device after attaching the balls?A: If you wait until the device and the perform cool down to room temperature, you will find that the perform will pull away from the device without leaving any adhesive residue on the balls. This means that you should only have to remove the flux residue from the reballing operation. Select the best cleaning method for your particular flux formulation. See the cleaning report here.

Q: What type of flux is recommended when using the EZReball™ kit?A: We have evaluated the use of a no clean flux for this process and advise against it. A no clean flux will work, however, because of its mild activity, you will need to use a large volume of it. We recommend a water soluble paste flux for reballing.

Q: What paste flux is recommended?A: While both water soluable as well as no clean paste fluxes can be used with the EZReball™ reballing preforms we recommend a water soluable process chemistry. When BEST performs reballing services we use we use Alpha WS-809.

Q: Is BEST able to supply the preforms with solder balls of other alloys?A: If you supply us with solder balls of your preferred alloy in one of the sizes mentioned above, we can fabricate preforms for you.

Q: What is the shelf life of EZReball™ preforms? A: Provide for the following storage conditions for the solder ball preforms: The performs themselves have an almost unlimited shelf life when stored in a normal production environment. The solder balls may build up oxidation depending on storage conditions and time. The use of water soluble flux should overcome any solderability issues encountered as a result of long term storage.

Q: Can these preforms be used when paste printing is required on the device (such as found on ceramic BGAs)A: Yes they can be used for a eutectic attach on CBGAs. Use a StencilQuik™ stencil on the CBGA, squeegee paste into the apertures, then place the EZReball™ perform and process as you normally would. After reflow, remove the preform then carefully peel off the StencilQuik™ stencil. You can order EZReball™ performs with high temp solder balls for this application.

Q: Can I use EZReball™ preforms to turn QFNs in to a balled device?A: EZReball™ preforms have been used by both our customers and by our rework division to attach balls to our leadless device rework QFNs. This makes the rework process simpler, faster while improving first pass yields. See our paper on this technique.

Q: What reflow profile should I use for lead free BGA reballing using EZReball™?A: Use the profile as indicated below

Q: What reflow profile should I use for tin lead BGA reballing using EZReball™?A: Use the profile as indicated below

Q: What sizes of solder spheres are offered?A: We currently offer the following diameter solder balls: 0.38mm (0.015"), 0.46mm (0.018"), 0.51mm (0.020"), 0.56mm (0.022"), 0.61mm (0.024"), 0.64mm (0.025"), and 76mm (0.030"). Custom sizes can be accommodated with customer-provided solder balls or BEST can source different size solder balls.

Q: Why don’t you have preforms in stock?A: The volume of BGA patterns, pitches, and ball sizes, makes it costly to have so many options in inventory. Building preforms to order is the best way to ensure the customer is satisfied. Online orders typically receive a one (1) business day turnaround.